Texture-Based Differences in Eating Rate Reduce the Impact of Increased Energy Density and Large Portions on Meal Size in Adults.

Large portions and high dietary energy density promote overconsumption at meal times. This could be reduced by eating slowly. Two studies investigated whether texture-based reductions in eating rate and oral processing moderate consumption at breakfast in combination with variations in energy density and portion size. Adults attended 4 breakfast sessions (2 × 2 repeated-measures design) to consume rice porridge, combining a 45% reduction in eating rate [thin porridge (140 g/min) compared with thick porridge (77 g/min)] with a 77% increase in energy density (0.57 compared with 1.01 kcal/g) in study 1 [ = 61; aged 21-48 y; body mass index (BMI; in kg/m): 16-29] and a 50% increase in portion size (100% compared with 150%) in study 2 ( = 53; aged 21-42 y; BMI: 16-29). Oral processing behaviors were coded by using webcams. Porridge intake was measured alongside changes in rated appetite. Increases in energy density and portion size led to increases of 80% and 13% in energy intake at breakfast, respectively ( < 0.001), but only portion size increased the weight of food consumed (13%). The thicker porridges were consumed at a slower rate and led to 11-13% reductions in food weight and energy intake compared with the thin versions ( < 0.001). Combined, the least energy was consumed when the thick "slow" porridge was served with a lower energy density or smaller portion ( < 0.05). Although intake was reduced for the thick porridges, they were expected to be more filling than the thin versions and experienced as equally satiating postconsumption. Adults eat in response to external features of the food environment. An opportunity exists to use a combination of energy-density dilution, smaller portions, and natural variations in food texture to design meals that promote reductions in energy intake while maintaining satiety.